Tracing device

ABSTRACT

An improved case for the tracing device shown in Grandjean U.S. Pat. No. 3,055,113 issued Sept. 25, 1962, including a protective plastic sheet covering its glass tracing surface, a non-hardening adhesive between the glass surface and the inner liner or side wall support therefor including a groove for said adhesive to prevent leakage of powder from inside the device, integral inwardly extending bosses on said inner liner for holding the axles of the pulleys for operating the tracing mechanism in their proper locations, and annular recesses or seats for washers around the apertures in said inner liner through which the knobs extend for operating the pulleys to further seal the escape of powder from inside the device.

United States Patent [1 1 I Clark TRACING DEVICE [75] Inventor: Earl D.Clark, Bryan, Ohio [73] Assignee: The Ohio Art Company, Bryan, Ohio [22]Filed: Nov. 17, 1971 [21] Appl. No.: 199,493

[52] US. Cl 33/18 R, 33/1 M [51] Int. Cl B431 13/00 [58] Field of Search346/21; 161/192; 220/82; 33/18 R, 1 M, 23 C [56] References Cited UNITEDSTATES PATENTS 3,055,1 13 9/1962 Grandjean 33/18 R 2,543,561 2/1951Tracy 313/18 R 3,170,383 2/1965 Hunt 220/82 R 2,828,625 4/1958 Morphiset al..... 220/82 R 3,307,400 3/1967 Leroy 73/331 2,279,145 4/1942 Ryan161/192 [451 Sept. 25, 1973.

Primary ExaminerHarry N. Haroian Attorney-Hugh Adam Kirk [5 7] ABSTRACTAn improved case for the tracing device shown in Grandjean US. Pat. No.3,055,113 issued Sept. 25, 1962, including a protective plastic sheetcovering its glass tracing surface, a non-hardening adhesive between theglass surface and the inner liner or side wall support thereforincluding a groove for said adhesive to prevent leakage of powder frominside the device, integral inwardly extending bosses on said innerliner for holding the axles of the pulleys for operating the tracingmechanism in their proper locations, and annular recesses or seats forwashers around the apertures in said inner liner through which the knobsextend for operating the pulleys to further seal the escape of powderfrom inside the device.

1 Claim, 7 Drawing Figures PATENTEUSEHSM SHEET 1 BF 2 FIG.I

EARL D.

ATTORNEY PATENTED 3.760.505

sum 2 m 2 INVENTOR D. CL R EARL ATTORNEY BACKGROUND OF THE INVENTIONPreviously it has been a major problem in the production of the tracingdevice shown in the above mentioned Grandjean patent to seal the finemetallic powder within the box, particularly when the tracing surface isof glass and the box is of another material such as plastic.Furthermore, there have been problems re garding loosening of thepulleys from their joumalled mountings in the base of the box, thuscasuing slipping of the tracing mechanism and even inoperabilitythereof.

Since the tracing surface of the Grandjean et al device is of glass,there is the remote possibility that the device may be dropped and theglass broken which 'could produce dangerous splinters that would harm orcut a person nearby.

SUMMARY OF THE INVENTION Generally speaking, the tracing device shown inthe above mentioned Grandjean patent comprises a fluid tight box havinga base and side walls or inner liner made of platic, such aspolystyrene, a transparent tracing surface comprising a glass platecovering the top of the box, and a plastic frame or cover for holdingthe plate against the walls of the box and to the base. Inside the boxthere is placed a fine metallic powder which will coat the inner surfaceof the transparent glass top or plate to render it opague. Then alsoinside the box there is a stylus or courser which presses against thisinner surface of the glass plate and scrapes the powder therefrom toproduce a line, including a mechanism for operating this styluscomprising a pair of orthogonally movable rods, the ends of which areconnected to strings that pass around pulleys journalled inside the box.At least one of the pulleys connected to the string of each orthogonallymovable rod has a shaft which projects through the box usually adjacentthe transparent top for a knob for operating the pulleys. Thus byrotating the two knobs at different speeds and in different directionsthe stylus or courser may be caused to draw lines, designs, write, orthe like on the inner surface of the transparent top plate. When thedesign and lines are to be removed the box is then tilted upside downand shaken so that the powder again will cover the places where it hasbeen scraped off of the plate. In order to facilitate the powder and itseven distribution of the inner surface of the glass plate, there may beprovided together therewith small plastic balls or beads inside the box.The powder employed usually is a metallic powder, such as aluminum.

The improved features of this invention for the tracing device includemeans to prevent the escape of this metallic powder from inside the box.One such means comprises a groove in the inner liner adjacent theperipheral edge of the glass plate, which groove is filled with anon-hardening adhesive to maintain with age the seal between the plasticliner and the edge of the glass plate. Another such means comprisesannular recesses around both ends of the apertures in the inner linerthrough which the shafts for the knobs project, which recesses retainwashers, such as of felt. The lower washer is being held in place by theboss on the shaft for the knob and the upper washer is held in itsannular recess or seat by theframe that holds the glass plate againstadhesive in the groove in the inner liner and to the base of the box.

Between the glass plate and the frame there is also provided atransparent plastic film, such as of a polyester like polyethyleneterephthalate, which will retain the glass plate within the box in theevent it is broken. For locating and maintaining the position of thisplastic safety film, there may be provided one or more apertures alongits outer edge through which the shafts for the knobs project.

OBJECTS AND ADVANTAGES Accordingly it is an object of this invention toproduce an improved educational game or toy by which line pictures,designs and writing may be easily drawn and erased, which toy does notleak any of the powdered materials in which the lines are made.

Another object is to prevent any glass from escaping in the event thetoy is dropped or the transparent glass tracing surface is broken, thusmaterially improving the safety of the toy or game for children.

BRIED DESCRIPTION OF THE VIEWS The above mentioned and other features,objects and advantages and the manner of attaining them are describedmore specifically below by reference to an embodiment of this inventionshown in the accompanying drawings, wherein:

FIG. 1 is a plan view of the improved tracing device according to thisinvention with parts thereof broken away to show the mechanism for theoperation thereof;

FIG. 2 is an end view of the device shown in FIG. 1 in the direction ofarrow 2 2 with parts broken away to show the other features of theoperating mechanism and parts of the device;

FIG. 3 is a view similar to that shown in FIG. 1 but on a reduced scalefor showing the plastic safety or protective sheet for covering theglass plate, and its location over the driving knobs;

FIG. 4 is an enlarged and expanded edge view taken along line 4 4 ofFIG. 3 showing how the frame, plastic sheet, glass plate, inner liner,and base are assembled;

FIG. 5 is a bottom view of the inner liner shown in the previousfigures, showing the bosses for holding the shafts of the pulleys inposition and the recessed seats for washers around the shafts for theknobs;

FIG. 6 is an enlarged sectional view through one of the shafts of theknobs showing the recesses for the washers therearound; and

FIG. 7 is an enlarged sectional view through one of the pulleys showinga boss on the inner liner for holding its axle and pulley in positionagainst the supporting journal post for the pulley mounted on the base.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring primarily toFIGS. 1 and 2, the embodiment of the tracing device 10 shown thereincomprises a rectangular base tray or plate 11 having peripheral grooves12 and 13 into which the lower edges of the inner liner 20 and outerframe member 40 are sealed, either by an adhesive and/or fusion of theseparts, if made of plastic such as polystyrene. Both the inner liner 20and frame 40 have substantially L-shaped cross-sections and comprisetelescoping or nesting rectangular frames. Between the inner edges ofthese two frames and and seated in a shoulder groove 21 in the innerliner 20, is a top transparent cover or plate to complete a closed box15 within which are the operating parts of the tracing device. This box15 is thus composed of the base 11, inner liner 20 and transparent cover50 having an inside tracking surface, all of which parts are sealedtogether to form a fluid tight chamber 16. Within this chamber 16 thereis placed a small amount of a metallic powder that may be mixed withsmall plastic beads 56, which mixture is shaken inside the chamber 16without escaping therefrom, so that the powder coats the inner surface51 of the transparent glass plate 50, particularly when the device isshaken in an upside-down position. This shaking also removes any marksor spaces that have been scraped clean of the powder by the stylus orcourser 60, to cause the inner surface 51 to be completely opaque forfurther scratching thereon by the stylus 60.

The stylus, courser, or marker shown in FIGS. 1, 2 and 3 slides alongtwo orthogonal rods 61 and 62 which pass through apertures in the baseof the stylus 60. The upper pointed end 63 of the stylus 60 is heldagainst the surface 51 of the glass plate 50 by the tension in thestrings 65 and through the orthogonal rods 61 and 62, so as the stylus60 is moved it will scratch the powder 55 that is adhered to the plate50 from the plate to make the plate 50 transparent. This scratch appearsas a black mark looking inside the dark sealed box, in contrast with thelighter color or grey of the powder which normally coats this surface51. Opposite ends of the orthogonal rod 61 are connected to a continuousloop of thread or string 65 which is looped around pulleys 66 near thecorners of the box under the overhanging flange of the inner liner, andalso around a driving pulley 67 which is connected to an outer knob 68(see FIG. 6) by means of a shaft 69 that extends through an aperture 22in the inner liner 20. Similarly the orthogonal rod 62 has its outerends connected to another thread 75 which is looped around separatecorner pulleys 76 and a drive pulley 77 which is connected to an outerknob 78 by means ofa shaft 79 that also extends through another aperture23 in the inner liner 20. Thus by rotating the knobs 68 and 78 atdifferent speeds and in different directions the stylus or courser 60and its point 63 traces a line over the inner surface 51 of thetransparent plate 50 to remove the opaque inner powder coating thereon.

The corner pulleys 66 and 76 are mounted on separate bosses 17 and 18,which usually are formed integral with the molded base 11 and havecentral apertures through which shaft pins 71 (see FIG. 7) with heads 72hold the pulleys in the bosses 17 and 18. Similarly bosses 19 areprovided in two of the comers for journalling the drive pulleys 67 and77 (see also FIG. 6). In order to prevent loosening of the shaft pins 71there is provided inwardly extending bosses 26 and 27 from inside of theinner liner memer 20 (see FIG. 7) for holding the heads 72 of these pins71 and the pulleys 66 and 76 in position and prevent them from anyloosening or working out of their joumalled bosses 17 and 18 on the base11.

Referring now more specifically to FIG. 6, the driving pulley 67 or 77mounted on the integral boss 19 is shown to have a hub portion 73 whichjournals in an annular recess 32 provided on the inside of the liner 20,which recess 32 is sufficiently deep to include gasket or washer 33which may be made of felt, and seals the powder 55 from escaping throughthe aperture 22 or 23. The inner liner 20 also at the other end of theaperture 22 or 23 is provided with a similar annular recess 34 for anadditional washer or felt gasket 35 that is held in place by the underside of the outer frame member 40 to further seal any powder fromescaping along the shaft 69 or 79 from the inside of the box or chamber15.

The inner liner 20 may also be provided with an additional groove 37 inone side of its shoulder groove or offset 21 which extends clear aroundthe inside of this offset 21 and opens against the inner surface 51 ofthe glass plate 50. This groove 37 is filled with a nonhardeningadhesive 38 which adheres both to the glass 50 and to the plastic of theinner liner 20, and does not get hard, brittle, or crack with age so ascontinuously form a fluid tight seal between the glass 50 and the innerliner 20.

In order to prevent any particles of glass from the glass plate 50 fromfalling out of the box 15 in the event this plate 50 may be broken orshattered, there is provided a transparent plastic sheet 80 whichcompletely covers the top of the box 15 and is held in place not only bythe frame 40, but also by a pair of apertures 81 near the comers of thesheet 80 which surround the shafts 69 and 79 of the driving knobs. Thusif by accident the glass plate 50 is shocked sufficiently to cause it tobreak or crack, any particles of the glass will remain inside thechamber 16 of the box 15 and no sharp edges will escape to injure theuser of the device.

It is understood that although the different parts of the device aremade of plastic, and are sealed and/or adhered together, other materialsmay be used for the parts of this tracing device without departing fromthis invention.

Thus, while there is described above the principles of this invention inconnection with specific apparatus, it is to be clearly understood thatthis description is made only by way of example and not as a limitationto the scope of this invention.

I claim:

1. In a tracing device comprising:

a fluid tight box having a transparent glass top plate,

a bottom, having integral upwardly extending bosses for holding thelower ends of shafts for pulleys,

side walls having an inwardly extending flange for supporting said topplate,

a frame around said side walls, anchored and sealed to said bottom andcovering the outer edges of said top plate,

powder in said box which can cover the inside surface of said top plateto make it opaque,

a stylus movable in said box for scraping the powder from said surfaceto form a line,

pulley means joumalled in said box for strings for moving said stylus,and

manual means projecting outside said box through said frame foroperating said pulley means, the improvement in said side walls of saidbox comprismg:

integral inwardly extending bosses for holding the upper ends of theshafts for said pulleys,

grooves in said flange adjacent the edges of said top plate for anonhardening adhesive to seal said top plate to said side walls toprevent the escape of said powder,

6 plate having its edges under said frame and being held in place by aportion of the manual means that projects outside said box, said sheetretaining any parts of said glass top within said box in case said glassplate is broken.

1. In a tracing device comprising: a fluid tight box having atransparent glass top plate, a bottom, having integral upwardlyextending bosses for holding the lower ends of shafts for pulleys, sidewalls having an inwardly extending flange for supporting said top plate,a frame around said side walls, anchored and sealed to said bottom andcovering the outer edges of said top plate, powder in said box which cancover the inside surface of said top plate to make it opaque, a stylusmovable in said box for scraping the powder from said surface to form aline, pulley means journalled in said box for strings for moving saidstylus, and manual means projecting outside said box through said framefor operating said pulley means, the improvement in said side walls ofsaid box comprising: integral inwardly extending bosses for holding theupper ends of the shafts for said pulleys, grooves in said flangeadjacent the edges of said top plate for a nonhardening adhesive to sealsaid top plate to said side walls to prevent the escape of said powder,apertures in said flange having recesses for washers through which saidmanual means project outside said box, and said manual means havinghub-portions for holding said washers in said recesses to preventleakage of said powder from said box, and a further improvement in saiddevice including a transparent plastic safety sheet covering said topplate having its edges under said frame and being held in place by aportion of the manual means that projects outside said box, said sheetretaining any parts of said glass top within said box in case said glassplate is broken.